The hedge fund manager owns 19.5 million shares in the pharmaceutical company, having bought them at the start of the year when the stock was trading between $160 and $202 a share. Ackman spent roughly $3.3 billion on the bet and has now lost roughly $1.8 billion on the position, an investor in his fund said on Wednesday.

Valeant’s stock price was off 29 percent, changing hands at $103.80 in early afternoon trading. A report from an influential short-seller that accused Valeant of fraud kicked off the sharp drop.